The dough:

1. In the bowl of a stand mixer, fitted with a hook, combine flour, salt, sugar, eggs, and yeast diluted in a little milk.

2. Knead the mixture and add the butter in pieces. Work the dough well to make it elastic. Make a ball and place it in a bowl covered with plastic wrap, and place it in a warm place for 5 hours.

3. On a floured surface, divide the dough into small balls the size of a golf ball. Cover them with a clean towel and let rise for 1 hour.

While the dough rises, prepare the filling.

Filling:

4. Put the sugar and water in a saucepan, and cook until the syrup reaches 51°C (124°F). Stop cooking as soon as it starts boiling.

5. Once the syrup has cooled, add the butter in pieces and the 1/2 vanilla bean, split and scraped.

6. Cook the waffles in a hot waffle iron. As soon as they come out of the mold, open each waffle in half and fill with the sugar and butter filling and vanilla.